You may have heard the saying ‘once in a blue moon’, but how about once in a blue supermoon?
On Wednesday and Thursday nights, Australians will be able to witness two rare lunar events, as a supermoon and a blue moon are set to coincide.
This will be the last chance to see a blue supermoon until 2029, according to Weatherzone.
Don’t expect it to be as spectacular as a lunar eclipse; this rare occurrence is more subtle.
This week’s full moon will mark the second full moon of the month, an occurrence known as a blue moon.
Unfortunately, that means the Moon won’t actually appear blue.
A supermoon occurs when the Moon is full as it reaches the point of its orbit where it is the closest to Earth.
“The Moon doesn’t go around the Earth in a circular orbit,” Astronomical Society of Victoria learner and planetary section director Stewart Beveridge said.
“It’s what they call elliptical [orbit], or kind of … egg-shaped, so the Moon tends to drift closer to the Earth and further from the Earth in its orbit.”
Source: YouTube/@NASAPJL EDU
The farthest point in the Moon’s ellipse is on average 405,500 kilometres from Earth.
The closest point is still a fair distance away, at about 363,300 kilometres; this means the supermoon might appear about 14 per cent larger than the average full moon.
But although the Moon may appear slightly bigger and brighter, Mr Beveridge said it’s unlikely you’ll notice much difference between a blue supermoon and a regular full moon.
If you’re still keen to catch a glimpse of the blue supermoon – it is a pretty rare event, even if it won’t look much different – NASA predicts the blue supermoon will be visible from Wednesday, August 30, in the US.
While this means the full moon may peak during Australia’s late Thursday morning, you should still be able to catch a glimpse of it on Wednesday and Thursday night as long as the sky isn’t too cloudy, Mr Beveridge said.
“The easiest thing to do is to go out on Wednesday or Thursday night and just look,” he said.